Mary Vincent invested in a single Capitol Hill property nearly five decades ago. Last week she finally cashed out, in a very big way. Vincent, a D.C. resident since the 1960s, purchased 325 Pennsylvania Ave.…

Mary Vincent invested in a single Capitol Hill property nearly five decades ago. Last week she finally cashed out, in a very big way.

Vincent, a D.C. resident since the 1960s, purchased 325 Pennsylvania Ave. SE for $70,000 in July 1970. On Nov. 15, her LLC, Sincerely Yours, sold it for $1 million — a 1,328 percent return on investment.

“It has turned out to be a very good buy,” said Vincent, who’s operated telephone answering and notary services out of building for many years. “Anything on Pennsylvania Avenue is automatically an asset, especially in the District of Columbia.”

The buyer of the 1,900-square-foot building, located two blocks from the U.S. Capitol grounds, is an affiliate of the ground-floor tenant, Can Yurdagul, the owner of Sushi Capitol. Yurdagul owns a number of restaurants in the District including Mirai in Shaw and Sushi Ogawa in Kalorama.

Vincent moved to D.C. from West Virginia decades ago to work at Acacia Life Insurance Co. But she decided to branch out…